I think my 12v battery is dead like others on the forum. Car shut down at an intersection and now I am stuck in the middle of no where. Suck 
waiting for tow truck.
waiting for tow truck.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
12v battery problem and stranded!
- Thread starter simplesolar
- Start date
OUCH! Hope you got it taken care of quickly and returned home last night. Let us know the outcome.I think my 12v battery is dead like others on the forum. Car shut down at an intersection and now I am stuck in the middle of no where. Suck
JPP
Active Member
...I have now placed an old set of jumper cables into the trunk storage area, so that if I have the dreaded 12V failure I can pop the nosecone, get a jump and maybe limp home.
Mario Kadastik
Active Member
Sparrow
S105/ Roadster 189
My 12 volt battery failed a week ago and the car was undriveable, but I was still able to open doors and frunk and the interior lights still came on. I measured the voltage at 11.5 volts at the time. This failure occurred one week after the battery had been replaced proactively. The fix was to replace the DC/DC converter.
JPP
Active Member
Crawl into the trunk if necessary (flipping the rear seats down as appropriate) to get to the storage well. Note that I do not keep them in the frunk (though could use the mechanical release uner the passenger dash). The nosecone comes out without opening the frunk.
Babylonfive
Power12
ChadS
Last tank of gas: March 2009
A few months ago I took my car in to get the storage cubby installed, and asked about the 12V issue. I was told some cars had issues, but mine was not on the list so it should be fine.
Last week I took my car back in for its 1-year service check...and this time they told me that they were going to give me a new 12V "just in case". (I have never had a problem) So their response to the issue has changed...it is still unclear to me whether the problem is the battery, the DC/DC converter, the firmware that decides when to charge the 12V, vampire drains, etc. Most likely it is a combination.
I did have a problem in the Roadster once. There were similar issues there, and after a couple of years my 12V battery got too weak to unlock the car (fortunately the top was off so I could just reach in and open them, and the car did start). Tesla gave me a new 12V battery under warranty. Then a couple of months later, they called me and told me they wanted to give me ANOTHER 12V battery, because the one they gave me wasn't good enough.
Last week I took my car back in for its 1-year service check...and this time they told me that they were going to give me a new 12V "just in case". (I have never had a problem) So their response to the issue has changed...it is still unclear to me whether the problem is the battery, the DC/DC converter, the firmware that decides when to charge the 12V, vampire drains, etc. Most likely it is a combination.
I did have a problem in the Roadster once. There were similar issues there, and after a couple of years my 12V battery got too weak to unlock the car (fortunately the top was off so I could just reach in and open them, and the car did start). Tesla gave me a new 12V battery under warranty. Then a couple of months later, they called me and told me they wanted to give me ANOTHER 12V battery, because the one they gave me wasn't good enough.
I am not sold on the 12v batteries Tesla is using. I know there are a few lithium ion 12v batteries out there but they are probably very expensive. I have been through a few 12v batteries on my Model S. I recently got the 12v battery low warning again and recently replaced the battery with an Odyssey 900 CCA 12v battery. I have ran these batteries for years in heavy duty applications and they have never let me down. We will see if it works out with the Model S but I would rather spend a few hundred and fix the problem permanently than have to deal with this problem again.
The original 1.5 roadster actually used a part of the main pack to power the 12v accessories. I think some law was enacted though that forced car manufacturers to have a separate 12v battery, so that was changed in subsequent models.
The original 1.5 roadster actually used a part of the main pack to power the 12v accessories. I think some law was enacted though that forced car manufacturers to have a separate 12v battery, so that was changed in subsequent models.
Check the voltage with which the battery is "charged" by the DC DC.
It should be above 13.5v or over 13.8 at least. If not, it is not the
battery that is faulty. If it is undercharged, especially to low 12v ish
or below, it will sulphate very quickly and become unusable.
If it undercharges, they need to replace or fix the DC DC unit.
In meantime, you can mitigate it by having a 12v battery charger charge the battery
every time you charge the car at home or somewhere where you have a 110v or 220v
plug. But that is not a solution. Just to get by.
It should be above 13.5v or over 13.8 at least. If not, it is not the
battery that is faulty. If it is undercharged, especially to low 12v ish
or below, it will sulphate very quickly and become unusable.
If it undercharges, they need to replace or fix the DC DC unit.
In meantime, you can mitigate it by having a 12v battery charger charge the battery
every time you charge the car at home or somewhere where you have a 110v or 220v
plug. But that is not a solution. Just to get by.
Mayhemm
Model S P85+ "Lola"
I'm curious as to how you found a compatible aftermarket battery? I've heard Model S batteries are quite involved and difficult to access as well (the battery itself, not the terminals exposed by removing the nosecone)
I have had my DC-DC replaced as well. The issue was definitely a failed 12v. Under load the CCAs would drop to 185 and 11.8v.
Requires partial disassembly of the frunk. Battery is located by the passenger side windshield cowl. Not that difficult. I pulled the battery, took it to my local odyssey dealer and we matched a battery that would work.
And how do you pop the trunk with failed 12V? [MK]
Hatch has no mechanical release found so far. I hope there actually IS one!
MS 12v battery is (roughly) equivalent to UB12350 - 12v 35AmpereHour U-1 AGM (absorbent Glass Mat) Lead Terminal $95.00 in lots of six. Sold by Battery Systems located in major cities. Available 'at all times' since it is a standard wheelchair battery. The UB12350 is 'deep cycle' whereas the latest MS battery reportedly is 'kinda deep cycle'.
--
Hatch has no mechanical release found so far. I hope there actually IS one!
MS 12v battery is (roughly) equivalent to UB12350 - 12v 35AmpereHour U-1 AGM (absorbent Glass Mat) Lead Terminal $95.00 in lots of six. Sold by Battery Systems located in major cities. Available 'at all times' since it is a standard wheelchair battery. The UB12350 is 'deep cycle' whereas the latest MS battery reportedly is 'kinda deep cycle'.
--
islandbayy
Active Member
There is a manual trunk (hatch) release cable by the trunk (hatch) light behind a plastic cover
Tommy
Member
@SMOP can you provide us the group # of the Odyssey battery; better yet the particular Odyssey battery you used. Mileage wise, I will be out of warranty this time next year and I too don't mind spending a bit more to get a good quality battery to avoid having battery related problems.
>I want to say a group 75 battery [Smop]
The U-1 (form factor) battery I listed has POS on left NEG on right. MS is reversed: U1R. Also the posts are made to accept a vertical bolt that ties several cables to the POS terminal. U1R is only available NON-AGM at the present time according to Battery Systems, so there is liquid acid inside (no glass matting) but this should not be significant. But they are deep cycle!
If you install remote terminals inside the Frunk then you can quickly connect a U1 battery into the 12 volt system should you find reason to do so. Or any other 12v battery for that matter.
>And how do you pop the trunk with failed 12V? [MK]
@islandbayy: The video you reposted does not answer this question assuming 'trunk' to mean HATCH.
Ok, I levered off the plastic cover and my MS does have the manual release cable to open Hatch. Pry yours off a few times to make it easier to do. This in a car with NO 3rd seats. Problem solved, thanx!
--
The U-1 (form factor) battery I listed has POS on left NEG on right. MS is reversed: U1R. Also the posts are made to accept a vertical bolt that ties several cables to the POS terminal. U1R is only available NON-AGM at the present time according to Battery Systems, so there is liquid acid inside (no glass matting) but this should not be significant. But they are deep cycle!
If you install remote terminals inside the Frunk then you can quickly connect a U1 battery into the 12 volt system should you find reason to do so. Or any other 12v battery for that matter.
>And how do you pop the trunk with failed 12V? [MK]
@islandbayy: The video you reposted does not answer this question assuming 'trunk' to mean HATCH.
Ok, I levered off the plastic cover and my MS does have the manual release cable to open Hatch. Pry yours off a few times to make it easier to do. This in a car with NO 3rd seats. Problem solved, thanx!
--
Last edited:
Similar threads
